Remote control for hydraulic systems



March 4, 1947. I s. A. WALDIE 2,416,860

I REMOTE CONTROL FOR HYDRAULIC SYSTEMS Filed May 8,1943 2 Sheets-Sheet 1 INVENTOR Game: A wawlz,

ATTORNEYS March 4, 1947. G. A. wALDlE 2,416,860

Patented Mar. 4, 1947 2,416,860 lisMorn CONTROL FOR HYDRAULIC George A. Waldie, Edis SYSTEM on, Ohio, assignor to The Hydraulic Development Corporation, Inc., Wilmington, Dcl., a corporation of Delaware Application .May 8, 1943, Serial No. 486,115

11 Claims.

This invention relates to remote controls and, in particular, to remote controls for use in hydraulic systems.

It is an object of this invention to provide a simplified remote control for hydraulically operable means, in which the operation of a control member or mechanism is hydraulically transferred to the hydraulic means to be controlled, to bring about an operation thereof.

It is a further object to provide a hydraulic system which includes hydraulic means to be controlled and manually operable means arranged remote from and hydraulically connected to said hydraulic means, and in which the operation of said manually operable control means brings about a variation in the flow of fluid through said means to be controlled.

It is also an object of this invention to provide a hydraulic system including fluid operable motor means, in which the motor means is operable automatically to vary its speed during its movement in one and the same direction, and in which the respective individual speeds during this movement are adapted to be controlled by means remote from and hydraulically connected to said motor means. v

It is a further object to provide a throttle valve, particularly for use in connection with hydraulic remote control systems, in which the valve comprises a plurality of 'stationary choke valves, and in which a variable choke valve cooperates with said stationary choke valves.

These and other objects and advantages of the invention will appear more clearly from the fol lowing specification in connection with the accompanying drawings, in which: I

Figure 1 diagrammatically illustrates a first embodiment.

Figure 2 illustrates the remote control of the present invention in connection with motor means adapted to be controlled so as to run at difierent speeds during on and the same stroke.

Figure 3 is a section through a valve which is particularly advantageous when used in connection with the control systems of Figures 1 and 2.

Figure 4 is asection along the line 4-4 of Figure 3. I

GENERAL ARRANGEMENT The control system according to the present invention substantially comprises a plurality of stationary fluid flow restrictions and a fluid operable throttle hydraulically connected with a manually operable choke. The arrangement is such that once the manually operable choke has been adjusted, a predetermined flow of fluid will occur through the fluid operable throttle. By varying the adjustment of the manually operable choke, the pressure conditions at the fluid operable throttle are changed in such a manner that the 2 I said throttle occupies. a diflerent position in which a change in the flow of fluid through said throttle will occur. By connecting this hydraulic control system with fluid operable mo- 6 tor means, the speed of, the motor means can -easily be controlled.

'Srnoomsr. AnsAucrmmr First embodiment therein comprises a fluid operable motor in which ma be of any standard type adapted to be operated by pressure fluid. The inlet side of the motor III is connected through a pressure line H with the delivery side of. a fluid pressure source of variable delivery which may be or any desired type and, in this instance, is a variable delivery pump l2. The pump has associated therewith a means of a plunger l5, continuously urges the pump l2 into full delivery position. The thrust of the spring I4 is adjustable by means of an adjusting screw [6. Also connected to the pump i2 is a control cylinder. ll having reciprocably mounted therein a fluid operable plunger l8 adapted, in response to fluid pressure acting thereupon, to reduce the delivery of the pump l2 against the thrust of the spring [4. The suction side of the pump I2 communicates through a suction line IS with a fluid reservoir or tank 20. Also connected with the tank 20 is an exhaust line 2| leading to a fluid flow restriction 22 which, in its turn, is connected to a conduit 23. The conduit 23 communicates with a fluid operable throttle valve generally designated 24. The valve 24 has reciprocably mounted therein a valve member 25 having connected thereto a piston portion 26 and ill a piston portion 21. The piston portion 26 is re- 40 ciprocable in a bore 28, whereas the piston portion 21 is reciprocable in a bore 29. The bore 28 is in continuous fluid connection with the bore 29 through a passageway 30 extending from one end of the valve member 25 through the other end thereof. The dimensions of the piston portions 26 and 21 of the valve member 25 are preferably such that the eflective area on one side of the piston portion 26 equals the eiiective area on the other side of the piston portion 26. It is, however, understood that the two opposed effective areas need not necessarily equal or substantially equal each other, but that the invention will also through a conduit 32 with the conduit 33. The

conduit 33 has'one end in fluid communication with a fluid flow restriction 34, the other end of spring chamber l3 housing a spring M which, by

work properly if the said opposed areas difier ma- 1 haust line 2 I which communicates through conduit 35 with the conduit 2|. The fluid flow restrictions 22 and 34 are preferably so dimensioned. that the section of the bore 36, pertaining to the fluid flow restriction 22, is greater than the section of the 5 bore 31 pertaining to the fluid flow restriction 34. -The conduit 33 contains a manually adjustable choke 38 and communicates with the outlet conduit 39. One end of the conduit 39 leads to an l annular recess 40 in the valve 24. The fluid con-' nection between the recess 46 and the outlet port in the throttle 24 is controlled by the valve means 25. Branching oil from the conduit 33 is a conduit 42' leading to the control cylinder i1.

Operation,

It may be assumed that the pump l2 has been i started while all parts occupy the position shown in Figure 1. Pressure fluid will then be .delivered by the pump I2 through the pressure line I I to the motor l0 and actuate the same. ,The exhaust fluid expelled from the motor l6 passes through conduit 39 through the partially opened choke 38 and from here in part through the fluid flow restriction 34 into the exhaust line 2|, and 2b in part through conduit 32 beneath the lower area ofthe piston portion 26. Anotherportion of the fluid expelled by the motor Ill into the outlet conduit 39 passes through the recess 40 and the port 4|, into the conduit 23. From here a portion of the fluid passes through conduit 3| into the upper portion of the bore 28 where it acts upon the upper area of the piston portion 26, while the other part of the fluid passes through the fluid flow restriction 22 into the ex- 35 It may be assumed that the choke 38 is so adjusted that the'pressure difierence acting upon the efiective upper area of the piston portion 26 and the efiective lower' area of the V piston portion 26 causes the valve member 25 to 40 occupy the position shown in Figure 1. It will i now be clear that in view of the respective positions of the choke 38 and the valve member 25,

, e, predetermined back pressure will prevail in the outlet conduit 39. This back pressure will react through conduit 33 and the conduit 42 upon the plunger It so as to place the same in' a position in which the fluid pressure acting upon the plunger l8 and the thrust of the spring 13 are balanced. The pump I2 will therefore occupy 5 a predetermined delivery position, and the motor I6 will'be operated at a predetermined speed.

If it is now desired to vary the speed of the motor I6, for instance, to increase the speed of p the motor I0,/it is merely necessary to decrease the pressure in the conduit 39. To this end the operator actuates the choke 38 so -'asto reduce the restriction thereof. Consequently, the pressure between the choke 38 and the fluid flow restriction 34 will increase, which increased pres- 0 sure will act upon the lower effective area of the piston portion 26, thereby moving the valve mem- .ber 25 somewhat upwardly. As a result thereof, the restriction between the annular recess 46 and the outlet port 4! is reduced so that more fluid passes therethrough. Consequently, the pressure in the conduit 23 will increase and this increased pressure will be conveyed through the pilot line 3| to the upperefiective area of the piston portion 26. The pressure upon the upper and lower effective areas of the piston portion 26 will move the valve member .25 into a balanced position, the net result of which will be a decreased pressure in the conduit 39. This decreased pressure will be. conveyed'through conduits 33 and 42 to. the

. 4 control cylinder l1 so that the spring M. will increase the delivery of the pump l2. Therefore, an increased quantity. of fluid will now be delivered by the pump 12 to the motor l6 which, therefore, will increase its speed.

If it-is desired to decrease the speed of the motor II], it is merely necessary to actuate the choke 38 so as to increase the flow restriction therethroug'n. It will be clear that in view of such operation, the pressure drop across the choke 38 will increase, or, in other words, the back pressure in conduit 39 will increase whereas the pressure in the conduit32 will decrease. quently, the pressure acting upon the upper effective area of the piston portion 26 will increase relative to the pressure acting upon the lower efiective area of the piston portion 26. As a result thereof, the valve member 25 will be moved downwardly, therefore restricting the fluid communication between the. recess 46 and the outlet port'4l, and a new balancing position wil1 be established for the valve member 25. .In view of the increased back pressure in conduit 39, which pressure acts through conduits 33 and 42 upon the plunger l8, the pump i2 is moved into a reduced delivery position against the thrust of the spring l4. A reduced quantity of fluid will now be delivered to the motor l6 so that the speed thereof will be reduced.

Second embodiment Referring now to Figure 2. the structure dis closed therein comprise a motor cylinder 43 having reciprocablymounted therein a plunger 44 with a piston portion 45. The left end of the motor cylinder 43 is connected through a conduit 46 with a four-way valve 41 of any standard design. The valve 41 communicates through a conduit 48 with the right hand end portion'of the cylinder 43. Also connected to the cylinder 41 is a pressure line 49 communicating with the delivery side of the pump I211. The pump 12a and the control means connected thereto fully correspond to the pump l2 and the'control means thereof so that the respective parts in Figure 2 have been numbered accordingly but with. the additional reference character a. The pump I 2a communicates through a suction line i 9a with a tank or fluid reservoir 20%, Connected to the tank 20a is a conduit 2 la, leading to astationary fluid flow restriction 22a with a bore 36a. The

. 41 is in another position it will interconnect the conduit 48 and pressure line 49 while simultaneously connecting the conduit 46 with the conduit 56. \i

' Branching off from the conduit 56 is a-conduit 5! leading to a two-way valve 52 whi h. when in open position, establishes fluid communication between the conduit 5| and the conduit 53. The

two-way valve 52 is continuously urged 'intoits ,open position by means of a spring 54 and is provided with a-roller 55 adapted to cooperate with a cam generally designated 56. The cam 56, which is connected in any convenient manner Conseto the plungr 44, has cam areas 51 and 56 which, when engaging the roller 65, allow the spring 54 to move the two-way valve 52 into its open position. The cam 56 is also provided with a cam area 59 which, when engaging the roller 55, closes the valve 52 against the thrust oi. the spring 64.

The conduit 53 contains a manuallyoperable choke 66' and-leads to the lower portion of the bore 26a pertaining to the throttle 24a. Branching oil from the conduit is a conduit 6| leading to a two-way valve 62 01 the same construction as the valve 52. The 'valve 62 is also provided with a spring 63 continuously urging the valve 62 into its open position in which fluid communication is established between the conduit 6| and the conduit 64. The valve 62 also includes a roller for cooperation with a cam generally designated 66. When the roller 66 engages the cam area 61, the spring 63 opens the valve 62. However, when the roller 65 is engaged by the cam area 66, the valve 62 i closed against the thrust of the spring 63. The cam 66 is likewise 6 of the choke l9 and the inlet 'of the flow restric- .tion 34a is conveyed to the lower portion of the connected in any convenient manner to the plunger 44 and. ii desired, may be integral with the cam 56. The conduit 64 comprises a manualy operable choke 69 and leads to the conduit 53 Also branching off from the conduit 5| is a conduit 16 leading to a two-way valve 1| oi the same construction as the valves 62 and 52. The valve 1| is continuously urged into its open position by the spring 12 and is provided with a roller 13 for cooperation with a cam generally designated 14. Until the roller 13 engages the cam area 15 or the cam area 16, the valve II is in its I open position and when engaged by cam ll it is moved to its closed position. The cam 14 is likewise connected'to the plunger 44 and, if desired, may be integral with the cams 56 and 66. when the valve II is in its open position, 'fluid communicatlon is established between the conduit 16 and a conduit 18. The conduit I6 comprises a manually operable chokei9 and leads to the con-' duit 53. The conduit 53 communicates through a fluid flow restriction 34a having a bore 31a with the conduit 2|a. The conduit 5| is also connected through a inder Ila.

Operation It may be assumed that the pump |2a has been started and that the valve 41 occupies a position in which fluid connection is established between the pressure line 49 and the conduit 46 while simultaneously the conduits 46 and 56 communicate with each other. It may furthermore be assumed that the chokes 66, 69 and 19 are differently set, and that the cams 56, 66 and 14 oocupy the position shown in the drawing. With these assumptions, it will be clear that pressure fluid delivered by the pump 2a passes through conduit 46 into the left hand portion of the motor cylinder 43 where it will act upon the piston and move the latter rightwardly, valves 52,

l 62 and II being in open position. The fluid expelled during the beginning of the rightward movement ofthe plunger 44 escapes through conduit 46 into the conduit 56. Since at this time the two-way valves 52, 62 and 1| are in open position, a part of the fluid in conduit 56 passes through'conduit 5|, the valves 52, 62 and II, and the chokes 66, 69 and 19 into the conduit 53.

From here the fluid passes through the fluid flow conduit 66 with the control cylbore 26a. The other portion of the fluid in conduit 56 passesthrough the recess 46a and the port 4|a into the conduit 23a. From here the fluid passes through the flow restriction 22a and the line 2 la to the tank 26a.

The pressure prevailing in the conduit 23a is conveyed through the pilot line 3|a into the upper portion of the bore 26a. It may be assumed that the pressure acting upon the upper and lower eflective area of the piston portion 26a causes' the valve member 2511 to assume the position shown therein.

When the plunger 44 has moved rightwardly a predetermined distance, the cam area 11 comes into engagement with the roller thereby causing the valve H to close. Consequently, fluid communication betwgn the conduits l6 and 16 is interrupted and the back, pressure in conduit 56 will increase. This increased pressure is conveyed through the recess 46a, conduit 23a and pilot line 3 la to the upper portion of the bore 26a where it acts upon the upper valve member 250 in the manner described above so as to cause the valve member 25a to move downwardly. .As a result thereof, the fluid flow from conduit 56 into conduit 23a is reduced. The increased back pressure in conduit 56 also acts through conduit 66 upon the control plunger |6a so that the latter decreases the delivery of the pump l2a. Consequently, the speed of the plunger 44 will be reduced.

When the plunger 44 has thus advanced rightwardly at a reduced speed, the cam area 59 engages the roller and causes the valve 52 to close. This in turn creates an increased pressure in conduit 56, and as a result thereof, the delivery of the pump He and the speed of the plunger 44 will be further reduced in th manner described above.

When the plunger 44 has advanced at this second reduced speed a predetermined distance, the cam area 59 will leave the roller 55 so that the valve 52 opens again. At about the same time the cam area 68 engages the roller 65 and closes the valve 62. Assuming that the chokes 66 and 69 have the same dimensions and that the choke 66 has been set for a smaller restriction than the choke 69, it will be clear that the plunger 44 willnow advance at a speed greater than the second reduced s ed.

To reverse the plunger 64, the operator shifts any of the chokes 66, 69 and 1 9. These chokes may be arranged on a panel in easy reach of the operator and remote from the motor or other I parts of the hydraulic system.

Throttle The valve shown in Figure 3 substantially consists of a casing 6| closed at its ends by closures restriction 34a and exhaust line 2 la into the tank 26a. The pressure prevailingbetween the outlet 62 and 63 which may be connected to the casing 6| in any convenient manner. for instance, by screws 64 and 65. The casing 6| comprises a stepped bore 66 in which is reciprocably mounted a plunger 81 with'a piston portion 88. The plunger 81 has a longitudinal bore 89 which in- I terconnects the ends of the bore 86. Near the -lower end ofthe plunger 89 are provided radial bores 90 communicating with the longitudinal The lower portion of the plunger81 bore 89.

has a reduced diameter so that it forms an annular chamber with the adjacent wall of the stepped bore 86. This annular chamber communioates through a'-- restricted passageway 9| motor, said variable restriction having fluid operable means associated therewith for efiecting said variations, second conduit means connecting said motor outlet with exhaust and comprising a; fixed restriction adjacent said exhaust and an adjustable restriction adjacent said motor, means hydraulically connecting the inlets'of said fixed restrictions with the fluid operable means associated with! said variable restriction, and means bydraulically connecting said motor exhaust with said fluid operable control means whereby the adjustment of said adjustable restriction is efiective to vary the delivery of said source and, therefore.

portion of the bore 86 and the lower ehd of the plunger 81 communicates with an annular recess 96 which, in its turn, communicates with a port 91 adapted threadedly to be engaged by a conduit 98. The port 91 also communicates with a conduit 99.

As will be seen from Figure 3, the effective upper and lower areas of the piston portion 88 equal each other in the same manner as the efi'ective lower and upper areas of the piston portion 26 in the throttle 24. The passageway 94 corresponds to the fluid flow restriction 34 of Figure 1, while, the fluid flow restriction 22 of Figure 1 has its equivalent in the restricted passageway 9| of Figure 3. The annular recess 96 in Figure 3 corresponds to the annular recess 48 of Figure 1 while the conduit 39 of Figure 1 has its equivalent in the conduit 98' of Figure 3. Conduits 93, 95 and 99 of Figure 3 correspond to conduits 23. 32 and 33, respectively, of Figure 1. The operation of the throttle shown in Figures 3 and 4 corresponds to the operation of the throttle 24 of Figure 1 so that no further description appears to be necessary.

It will be understood that the present invention is by no means limited to the particular structure shown in the drawings, but also emthe speed of operation of said motor. 7

3. In a hydraulic system, a fluid source of variable delivery, fluid pressure responsive means alsociated with said source for varying the delivery thereof, fluid operable motor means having the inlet thereof connected with said source for receiving actuating fluid therefrom, a first conduit means connecting the outlet of said motor with exhaust and including a fixed restriction adjacent said exhaust and a variable restriction adjacent said motor, said variable restriction combraces any modifications within the scope of the I appended claims.

Having thus fully described my invention what I claim as new and desire to secure by Letters Patent is:

1. In a hydraulic system, a fluid source of variable delivery, fluid operable motor means having its inlet connected with said source to receive actuating fluid therefrom, a first conduit means exhaust and a variable restriction adjacent said prising a movable valve member having opposed fluid operable actuating means associated therewith, a second conduitmeans connecting said motor outlet with exhaust and including a. fixed restriction adjacent said exhaust and a 'manually adjustable restriction adjacent said motor,

conduit means hydraulically connecting one of said fluid operable actuating means with the inletof one of said fixed restrictions and the other of said fluid operable actuating means with the inlet of the other of said fixed restrictions whereby the actuation of said valve member is responsive to the pressures at the inlets of said fixed restrictions, and means hydraulically connecting said fluid pressure responsive means with the ininlet connected with said source for receiving actuating fluid therefrom, fluid pressure responsive means associated with said source for varying the delivery thereof and hydraulically connected with the outlet of said motor, and means for maintaining a predetermined pressure at said motormotor'outlet, a second conduit means connecting 3 for varying the delivery of said fluid source.

2. In a hydraulic system, a fluid source of variable delivery, fluid operable control means assoclated with said source for varying the delivery thereof, fluid operable motor means having its finlet connected with said source for receiving actuating fluid therefrom, first conduit means connecting said motor outlet with exhaust and comprising a fixed restriction adjacent said exhaust and a variable restriction adjacent said outlet comprising afirst conduit means connected from said motor outlet to exhaust and comprising a fixed restriction adjacent said exhaust and a variable restriction adjacent said motor, said var-i iable restriction comprising a reciprocable' valve member having associated therewith opposed and substantially equal fluid operable areas for reciprocalting said valvemember, a second conduit connecting said motor outlet to exhaust and including a fixed restriction adjacent said exhaust and a manually adjustable restriction adjacent said motor and conduit means respectively connecting said fluid operable areas with the inlets of said fixed restrictions whereby the adjustment of said manually adjustable restriction is effective to vary said variable restriction-and the varying of said variable restriction is efiective'to actuate said fluid pressure responsive means associatcd 'with said source.

5. In a hydraulic system, a fluid operable motor, a fluid source connected with the inlet of said motor for supplying actuating fluid thereto, fluid pressure responsive means associated with said source for varying the delivery thereof and by:-

draulically connected with the outlet of said motor, means for varying the pressure at said motor outlet thereby to actuate said fluid pres- .sure' responsive means to vary the delivery of areas with a point on said second conduit between the restrictions therein, said fluid operable haust and including a fixed restriction adjacent said exhaust and a plurality of manually adjustable restrictions connected in parallel adjacent said motor, each of said manually adjustable restrictions having associated therewith valve means eifective to disconnect said manually adjustable' restrictions from said motor outlet, means responsive to the travel of said motorfor selectively actuating said valve means, and means hydraulically connecting said opposed fluid operable areas of said variable restriction respectively with the inlets of said fixed restrictions.

6. In a hydraulic system, a fluid source, a fluid motor connected to receive fluid from said source, fluid pressure responsive means operable to vary the relative displacements of said source and motor and hydraulically connected with the outlet of said motor, a pair of paralleled conduits serially connected between said motor outlet and an exhaust and each comprising a pair of restrictions in series, manual means for adjusting at least one of the restrictions in one of said conduits, opposed fluid operable areas for adjusting one of said restrictions in the other of said conduits, and channel means connecting said fluid operable areas to said conduits between said restrictions.

7. In a hydraulic system, a pump and a motor connected in series, means for varying the relative displacements of said pump and motor, fluid pressure responsive means for actuating said dis placement varying means and. connected with the outlet of said motor, a pair of paralleled conduits connecting said motor outlet with an exhaust and each comprising a pair of restrictions in series, manual means for adjusting at-least one of the restrictions in one of said conduits, opposed fluid operable areas for adjusting one of the restrictions in the other of said conduits, and means hydraulically connecting said opposed flui operable areas with points on said paralleled conduits between the restrictions therein whereby said fluid operable areas are actuated in response areas being proportioned to exert equal thrusts when the system is in a state of balance.

9. In a hydraulic system, a pump, a motor suplied by said pump, fluid operable control means for varying the relative displacements of said pump and motor, a first flow restriction connected between said motor outlet and an exhaust, a variable flow restrictor connected between said first restrictor and said motor outlet, a second restrictor connected between said motor outlet and an exhaust, a manually adjustable flow restrictor'interposed between said second restrictor and said motor outlet for varying the rate of fluid flow through said second restrictor, means connecting said fluid operable control means with .ing a pair of restrictions in series, at least one of said restrictions in one of said conduits being variable and another of said restrictions in the other of said conduits comprising a plurality of restrictions in parallel, means operated in response to movements of the motor for making said paralleled restrictions selectively eflective, and fluid operable areas operable to vary said variable restriction and each connected with a to variations from a predetermined ratio of the pressures at said points.

8. In a hydraulic system, a pump and a motor connected in series, means responsive to the pres sure at said moto outlet for varying the relative displacement of said pump and motor, first and second conduits connecting said motor outlet with an exhaust and each including a pair of restrictions in series, one of said restrictions in one of said conduits being adjustable and another of said restrictions in the other of said conduits being variable, opposed fluid operable areas for efiecting the variations of said variable restrictor, means hydraulically connecting one of said fluid operable areas with a point on said first conduit between the restrictions therein, and means connecting the other of said fluid operable different of said conduits between the restrictions therein.

11. In a hydraulic system, a pressure fluid source, a fluid operable motor serially connected with said source to be actuated by pressure fluid therefrom, paralleled conduits serially connected between said motor outlet and an exhaust and each comprising a pair of flow restrictions in series, opposed fluid operable areas for adjusting one of said restrictions, and means connecting said fluid operable areas to be responsive to changes in the ratio of pressures in the said conduits at points between the restrictions therein.

. GEORGE A. WALDIE.

REFERENCES CITED The following references are of record in the file of this patent:

' UNITED STATES PATENTS "Name Date Kendrick Apr. 15, 1941 Douglas Oct. 6, 1936 Din'zl Nov. 1, 1938 Ernst, June 25, 1935 Doe Oct. 24, 1939 Alden May 7, 1935 Svenson Oct. 21, 1941 Number I Clark -1 July 18, 1939 Vickers June 2, 1942 Tweedale Aug. 26, 1941 Harrington Apr. 4, 1944 Tucker Apr. 24, 1945 Harrington Oct. 21, 1941p Vickers Dec. 4, 1934 

